The present invention relates to a method of and to an apparatus for accumulating piles of sheets of paper or the like. More particularly, the invention relates to a method and apparatus for stacking reams of paper, and for transporting the stacks on to a further processing station.
The invention is directed particularly to the accumulation of piles of sheets of paper, such as reams of 81/2" by 11" sheets of paper wrapped in heavy paper (500 sheets constituting a ream). Such reams are presently produced in vast quantities by means of an apparatus called a "sheeter" which cuts rolls of paper into sheets of the desired size (e.g., 81/2" by 11") and stacks the sheets in piles of 500 sheets and an apparatus called a "ream wrapper" which wraps the piles in a sheet of wrapping paper. The wrapped reams are fed into cartons which are closed with lids as generally described in U.S. Pat. No. 4,117,646. The reams are packed in the cartons in stacks. The reams can be accumulated into such stacks in the cartons themselves as disclosed in U.S. Pat. No. 4,150,523 or they can be accumulated into stacks prior to insertion into the cartons.
A problem presently confronting the industry is how to increase the speeds of the accumulating and cartoning apparatus so as to handle the increased numbers of wrapped reams being turned out by improved, high speed sheeters and ream wrappers.
One apparatus presently employed involves bottom feed accumulation or upstacking of piles. The piles are delivered to an elevator which then serially raises them until they are engaged and supported by dogs which grasp the undersides of the lowermost piles about their edges. The elevator is then lowered to its original position to receive other piles and the dogs continue to hold the preceeding piles. When the elevator receives succeeding piles, it lifts those piles which in turn contact and lift piles already being held by the dogs. The dogs thus engage the undersides of the most recently elevated or lowermost piles. This apparatus is unable to handle high volumes because of wasted idle motion and provides unacceptable support for the piles, particularly when operating at high speeds.